Processes for the production of organometallic compounds

ABSTRACT

This invention relates to processes for the production of organometallic compounds represented by the formula M(L) 3  wherein M is a Group VIII metal, e.g., ruthenium, and L is the same or different and represents a substituted or unsubstituted amidinato group or a substituted or unsubstituted amidinato-like group, which process comprises (i) reacting a substituted or unsubstituted metal source compound, e.g., ruthenium (II) compound, with a substituted or unsubstituted amidinate or amidinate-like compound in the presence of a solvent and under reaction conditions sufficient to produce a reaction mixture comprising said organometallic compound, e.g., ruthenium (III) compound, and (ii) separating said organometallic compound from said reaction mixture. The organometallic compounds are useful in semiconductor applications as chemical vapor or atomic layer deposition precursors for film depositions.

FIELD OF THE INVENTION

This invention relates to processes for producing organometallicamidinate compounds, a method for producing a film or coating from theorganometallic amidinate compounds, and ruthenium amidinate compoundsthat are hydrogen reducible and deposit in a self-limiting manner. Theorganometallic amidinate compounds are useful in semiconductorapplications as chemical vapor or atomic layer deposition precursors forfilm depositions.

BACKGROUND OF THE INVENTION

In existing semiconductor devices, transistors communicate with oneanother via an elaborate series of copper interconnects connectedthrough a series of metal layers above the transistor. To minimize thecapacitive coupling between these interconnects, the space between isoccupied by a material with a low dielectric constant (i.e., low-Kmaterials). To prevent the diffusion of copper into this low-K material,a composite barrier is put in place. Current practices use physicalvapor deposition techniques to accomplish this. An example of a BEOL(back end of the line) interconnects strategy for putting a barrier inplace by physical vapor deposition and electrochemical deposition is asfollows: low K repair, tantalum nitride reactive sputter physical vapordeposition, tantalum sputter physical vapor deposition, copper seedsputter physical vapor deposition and copper electrochemical deposition.

Physical vapor deposition techniques result in anisotropic deposition,with the thickness of the film on sidewalls being significantly thinnerthan the thickness of the film on the horizontal surfaces of the wafer.Since the ability of the barrier to prevent the migration of copperthrough to the low-K dielectric is proportional to the thickness of thebarrier, the barrier is thicker than it needs to be on the horizontalwafer surfaces.

As the semiconductor moves to future technology nodes, the dimensions ofinterconnects will decrease. This will result in a decrease of thesurface area to volume ratio of the interconnect, concomitant with anincrease in the volume occupied by the diffusion barrier. As the barrieroccupies more of the interconnect channel space, the effectiveresistivity of the interconnect increases for two reasons: first,decrease in the size of the interconnect and second, copper/barriersurface scattering of electrons becomes a more critical issue.

One method of minimizing these issues is to deposit films isotropicallyusing atomic layer deposition. Unfortunately, no chemistries exist thatcan deposit tantalum metal using atomic layer deposition. The role oftantalum in the deposition strategy described above is to generateadequate adhesion between the copper seed and tantalum nitride. Withouttantalum, copper delaminates from the tantalum nitride film compromisingdevice performance.

Another metal that may be viable within this application is ruthenium.Ruthenium is adherent to titanium nitride and thus one may expect thatit would be adherent to tantalum nitride, moreover, the use of rutheniumcould obviate the requirement of a copper seed layer since ruthenium hassufficient conductivity that copper electrochemical deposition could becarried out directly on a ruthenium film. An isotropic atomic layerdeposition strategy for forming BEOL interconnects using ruthenium is asfollows: low K repair, tantalum nitride atomic layer deposition,ruthenium atomic layer deposition and copper electrochemical deposition.

While there have been reports in the literature detailing rutheniumatomic layer deposition, all of them involve the use of either oxygen ora plasma. Oxygen based chemistries are incompatible with a BEOLintegration sequence since the presence of trace amounts of oxygenwithin the deposited film could diffuse into the copper channelresulting in the formation of copper oxides compromising deviceperformance. Similarily, concerns exist regarding the ability of plasmasto deposit isotropic films.

Ideally, a suitable BEOL atomic layer deposition process would becapable of using hydrogen, or other reducing gas, at temperatures below300° C. so that the deposition could be carried out in a mannercompatible with the rest of the BEOL integration strategy. In additionto being hydrogen reducible, chemistries should deposit in aself-limiting manner. In other words, in the absence of a reactant gas,the substrate should saturate with a monolayer, or fraction of amonolayer, of a dissociatively chemisorbed precursor.

The problem is that there are no known suitable hydrogen reducibleruthenium complexes of sufficient volatility for use as atomic layerdeposition precursors, and as such, no self-limiting, hydrogen reducibleprecursors have been identified. It would therefore be desirable in theart to develop self-limiting, hydrogen reducible ruthenium complexessuitable for BEOL atomic layer deposition processes.

Further, the synthetic processes utilized to generate organometallicprecursors are highly important, and must insure safety, high purity,throughput, and consistency. The economics associated with suchprocesses together with the rigid requirements of the electronicsindustry make the synthesis of organometallic precursors challenging.Developing a methodology for producing organometallic precursors thataddresses the aforementioned potential hold-ups would be beneficialtoward establishing the production of these materials for use in theelectronics industry.

Processes for preparing organometallic compounds include those disclosedin U.S. Patent Application Publication No. US 2004/0127732 A1, publishedJul. 1, 2004. Organometallic precursor compounds may also be prepared byprocesses such as described in Vendemiati, Beatrice et al., ParamagneticBis(amidinate)Iron(II) Complexes and their Diamagnetic DicarbonylDerivatives, Euro. J. Inorg. Chem. 2001, 707-711; Lim, Booyong S. etal., Synthesis and Characterization of Volatile, Thermally Stable,Reactive Transition Metal Amidinates, Inorg. Chem., 2003, Preprint; andreferences therein.

A need exists for new processes for making organometallic precursorsthat give higher product yields, operate efficiently, provideconsistency and permit easier scale up for production quantities oforganometallic compounds. It would therefore be desirable in the art toprovide new processes for making organometallic compounds that addressthese needs.

Also, in developing methods for forming thin films by chemical vapordeposition or atomic layer deposition methods, precursors thatpreferably are hydrogen reducible, deposit in a self-limiting manner,liquid at room temperature, have adequate vapor pressure, haveappropriate thermal stability (i.e., for chemical vapor deposition willdecompose on the heated substrate but not during delivery, and foratomic layer deposition will not decompose thermally but will react whenexposed to co-reactant), can form uniform films, and will leave behindvery little, if any, undesired impurities (e.g., halides, carbon, etc.)are highly desirable. A need exists for developing new compounds and forexploring their potential as chemical vapor or atomic layer depositionprecursors for film depositions, in particular self-limiting, hydrogenreducible organometallic complexes for atomic layer deposition asindicated above. It would therefore be desirable in the art to provideprecursors that possess some, or preferably all, of the abovecharacteristics.

SUMMARY OF THE INVENTION

This invention relates to processes for the production of organometalliccompounds selected from the following:

(1) a process for the production of an organometallic compoundrepresented by the formula (L)₂M(L′)₂ which process comprises (i)reacting a substituted or unsubstituted metal source compoundrepresented by the formula MX₂R with a substituted or unsubstitutedamidinate or amidinate-like compound represented by the formula A₁L anda ligand source represented by the formula L′, in the presence of asolvent and under reaction conditions sufficient to produce a reactionmixture comprising said organometallic compound, and (ii) separatingsaid organometallic compound from said reaction mixture; and

(2) a process for the production of an organometallic compoundrepresented by the formula M(L)₃ which process comprises (i) reacting asubstituted or unsubstituted metal source compound represented by theformula MX₂R, e.g., ruthenium (II) compound, with a substituted orunsubstituted amidinate or amidinate-like compound represented by theformula A₁L in the presence of a solvent and under reaction conditionssufficient to produce a reaction mixture comprising said organometalliccompound, e.g., ruthenium (III) compound, and (ii) separating saidorganometallic compound from said reaction mixture;

wherein M is a Group VIII metal, X is a halogen group, R is asubstituted or unsubstituted hydrocarbon group, A₁ is an alkali metal, Lis the same or different and represents a substituted or unsubstitutedamidinato group or a substituted or unsubstituted amidinato-like group,and L′ is the same or different and represents N₂ or a substituted orunsubstituted heteroatom-containing group.

This invention also relates to organometallic ruthenium compoundsrepresented by the formula

wherein R₁, R₂, R₃, R₄, R₅ and R₆ are the same or different and eachrepresents hydrogen, a halogen atom, an acyl group having from 1 toabout 12 carbon atoms, preferably from 1 to about 6 carbon atoms, analkoxy group having from 1 to about 12 carbon atoms, an alkoxycarbonylgroup having from 1 to about 12 carbon atoms, preferably from 1 to about6 carbon atoms, an alkyl group having from 1 to about 12 carbon atoms,preferably from 1 to about 6 carbon atoms, an amine group having from 1to about 12 carbon atoms, preferably from 1 to about 6 carbon atoms, ora silyl group having from 0 to about 12 carbon atoms, preferably from 0to about 6 carbon atoms, and L₁ and L₂ are the same or different andeach represents N₂ or a substituted or unsubstitutedheteroatom-containing group. The organometallic ruthenium compounds arepreferably hydrogen reducible and deposit in a self-limiting manner.

This invention further relates to a method for producing a film, coatingor powder by decomposing an organometallic precursor compoundrepresented by the formula (L)₂M(L′)₂ above, thereby producing the film,coating or powder. Typically, the decomposing of said organometallicprecursor compound is thermal, chemical, photochemical orplasma-activated. Film deposition is preferably self-limiting andconducted in the presence of at least one reactive gas such as hydrogen.

This invention also relates to organometallic precursor mixturescomprising (i) a first organometallic precursor compound represented bythe formula (L)₂M(L′)₂ or M(L)₃ above, and (ii) one or more differentorganometallic precursor compounds (e.g., a hafnium-containing,tantalum-containing or molybdenum-containing organometallic precursorcompound).

This invention relates in particular to depositions involvingamidinate-based ruthenium precursors. These precursors may haveadvantages over the other known precursors, especially when utilized intandem with other ‘next-generation’ materials (e.g., hafnium, tantalumand molybdenum). These ruthenium-containing materials can be used for avariety of purposes such as dielectrics, barriers, and electrodes, andin many cases show improved properties (thermal stability, desiredmorphology, less diffusion, lower leakage, less charge trapping, and thelike) than the non-ruthenium containing films. These amidinate-basedruthenium precursors may be deposited by atomic layer depositionemploying a hydrogen reduction pathway in a self-limiting manner,thereby enabling use of ruthenium as a barrier/adhesion layer inconjunction with tantalum nitride in BEOL liner applications. Suchamidinate-based ruthenium precursors deposited in a self-limiting mannerby atomic layer deposition may enable conformal film growth over highaspect ratio trench architectures in a reducing environment.

The invention has several advantages. For example, the processes of theinvention are useful in generating organometallic compound precursorsthat have varied chemical structures and physical properties. Filmsgenerated from the organometallic compound precursors can be depositedin a self-limiting manner with a short incubation time, and the filmsdeposited from the organometallic compound precursors exhibit goodsmoothness.

This invention relates in particular to chemical vapor deposition andatomic layer deposition precursors for next generation devices,specifically amidinate-containing ruthenium precursors that areself-limiting, hydrogen reducible and are desirably liquid at roomtemperature, i.e., 20° C.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, this invention relates to processes for theproduction of organometallic compounds selected from the following:

(1) a process for the production of an organometallic compoundrepresented by the formula (L)₂M(L′)₂ which process comprises (i)reacting a substituted or unsubstituted metal source compoundrepresented by the formula MX₂R with a substituted or unsubstitutedamidinate or amidinate-like compound represented by the formula A₁L anda ligand source represented by the formula L′, in the presence of asolvent and under reaction conditions sufficient to produce a reactionmixture comprising said organometallic compound, and (ii) separatingsaid organometallic compound from said reaction mixture; and

(2) a process for the production of an organometallic compoundrepresented by the formula M(L)₃ which process comprises (i) reacting asubstituted or unsubstituted metal source compound represented by theformula MX₂R with a substituted or unsubstituted amidinate oramidinate-like compound represented by the formula A₁L in the presenceof a solvent and under reaction conditions sufficient to produce areaction mixture comprising said organometallic compound, and (ii)separating said organometallic compound from said reaction mixture;

wherein M is a Group VIII metal, X is a halogen group, R is asubstituted or unsubstituted hydrocarbon group, A₁ is an alkali metal, Lis the same or different and represents a substituted or unsubstitutedamidinato group or a substituted or unsubstituted amidinato-like group,and L′ is the same or different and represents N₂ or a substituted orunsubstituted heteroatom-containing group.

The metal source compound starting material MX₂R may be selected from awide variety of compounds known in the art. The invention herein mostprefers metals selected from Ru, Os and Fe. Illustrative metal sourcecompounds represented by the formula MX₂R include, for example,bis[dichloro(η⁶-benzene)ruthenium (II)],bis[dichloro(η⁶-toluene)ruthenium (II)], and the like. As indicatedabove, M is a Group VIII metal such as Ru, Os or Fe, X is a halogengroup such as fluoro, chloro, bromo and iodo, and R is a substituted orunsubstituted hydrocarbon group, preferably an unsaturated hydrocarbongroup, more preferably an aromatic compound such as η⁶-benzene,η⁶-toluene, and the like.

In a preferred embodiment of process (1) above, a ruthenium (II) sourcestarting material, e.g., bis[dichloro(η⁶-benzene)ruthenium (II)], can bereacted with an amidinate starting material, e.g., lithium(N,N′-diisopropylacetamidinate), and nitrogen gas to give a ruthenium(II) amidinate product, e.g., bisQ(N,N′-diisopropylacetamidinato)dinitrogenruthenium (II). In a preferredembodiment of process (2) above, a ruthenium (II) source startingmaterial, e.g., bis[dichloro(η⁶-benzene)ruthenium (II)], can be reactedwith an amidinate starting material, e.g., lithium(N,N′-diisopropylacetamidinate), to give a ruthenium (III) amidinateproduct, e.g., tris(N,N′-diisopropylacetamidinato)ruthenium (III).

The process of the invention is preferably useful in generatingorganometallic ruthenium compound precursors that have varied chemicalstructures and physical properties. A wide variety of reaction materialsmay be employed in the processes of this invention. For example, in thepreparation of the metal source compounds, ruthenium starting materialsthat may be used include commercial grade Ru(III) chloride hydrate,α-ruthenium(III) chloride, β-ruthenium(III) chloride, ruthenium(III)nitrate, (PPh₃)_(x)RuCl₂ (x=3-4) and the like.

The concentration of the metal source compound starting material canvary over a wide range, and need only be that minimum amount necessaryto react with the amidinate or amidinate-like compound and ligand sourcein process (1) above or the amidinate or amidinate-like compound inprocess (2) above, and to provide the given metal concentration desiredto be employed and which will furnish the basis for at least the amountof metal necessary for the organometallic compounds of this invention.In general, depending on the size of the reaction mixture, metal sourcecompound starting material concentrations in the range of from about 1millimole or less to about 10,000 millimoles or greater, should besufficient for most processes.

The amidinate or amidinate-like compound starting material A₁L may beselected from a wide variety of compounds known in the art. Illustrativeamidinate compounds represented by the formula A₁L include lithiumamidinates such as lithium (N,N′-diisopropylacetamidinate), lithium(N,N′-diisopropylformamidinate), lithium(N,N′-di-n-propylformamidinate), lithium(N,N′-di-n-propylacetamidinate), lithium (N,N′-diethylacetamidinate),lithium (N,N′-diethylformamidinate), lithium(N,N′-dimethylacetamidinate), lithium (N,N′-dimethylformamidinate),sodium amidinates above, bromomagnesium amidinates above, and the like.Illustrative amidinate-like compounds represented by the formula A₁Linclude negatively charged, chelating, four electron donor compoundssuch as lithium beta-diketonates, lithium allyls, lithiumdithiocarbamates, sodium amidinate-like compounds above, bromomagnesiumamidinate-like compounds above, and the like. Schiff bases and certainchelating alkylamines and arylamines such as2-[(dimethylamino)methyl]phenyl are illustrative nitrogen boundnegatively charged, chelating, four electron donor compounds. Asindicated above, A₁ is an alkali metal such as lithium, sodium andbromium and L is the same or different and represents a substituted orunsubstituted amidinato group or a substituted or unsubstitutedamidinato-like group.

The concentration of the amidinate or amidinate-like compound startingmaterial can vary over a wide range, and need only be that minimumamount necessary to react with the metal source compound and ligandsource in process (1) above or the metal source compound in process (2)above. In general, depending on the size of the first reaction mixture,amidinate or amidinate-like compound starting material concentrations inthe range of from about 1 millimole or less to about 10,000 millimolesor greater, should be sufficient for most processes.

The ligand source starting material L′ may be selected from a widevariety of compounds known in the art. The invention herein most prefersligand source starting materials selected from N₂, NCR₇, PR₇R₈R₉ orNR₇R₈R₉, wherein R₇, R₈ and R₉ are the same or different and eachrepresents hydrogen, a halogen atom, an acyl group having from 1 toabout 12 carbon atoms, preferably from 1 to about 6 carbon atoms, analkoxy group having from 1 to about 12 carbon atoms, preferably from 1to about 6 carbon atoms, an alkoxycarbonyl group having from 1 to about12 carbon atoms, preferably from 1 to about 6 carbon atoms, an alkylgroup having from 1 to about 12 carbon atoms, preferably from 1 to about6 carbon atoms, an amine group having from 1 to about 12 carbon atoms,preferably from 1 to about 6 carbon atoms, or a silyl group having from0 to about 12 carbon atoms, preferably from 0 to about 6 carbon atoms.Illustrative ligand source starting materials represented by the formulaL′ include, for example, two electron donor ligands such as nitriles,dinitrogen, amines, low molecular weight phosphines, and the like. Asindicated above, L′ is the same or different and represents N₂ or asubstituted or unsubstituted heteroatom-containing group.

The concentration of the ligand source starting material can vary over awide range, and need only be that minimum amount necessary to react withthe metal source compound and amidinate or amidinate-like compound inprocess (1) above. In general, depending on the size of the reactionmixture, ligand source starting material concentrations in the range offrom about 1 millimole or less to about 10,000 millimoles or greater,should be sufficient for most processes.

The ligand source material may also be used in process (2) above inamounts that it would not be expected to coordinate directly to thetransition metal. However, if the ligand source material is used insufficient amounts in process (2) above, it is expected thatorganometallic compounds represented by the formula (L)₂M(L′)₂ alongwith organometallic compounds represented by the formula M(L)₃ may beproduced. Likewise, if the ligand source material is used ininsufficient amounts in process (1) above, it is expected thatorganometallic compounds represented by the formula M(L)₃ along withorganometallic compounds represented by the formula (L)₂M(L′)₂ may beproduced.

Permissible substituents of the substituted amidinate and amidinate-likegroups (L), the substituted hydrocarbon groups (R) and the substitutedheteroatom-containing groups (L′, L₁ and L₂) include halogen atoms, acylgroups having from 1 to about 12 carbon atoms, alkoxy groups having from1 to about 12 carbon atoms, alkoxycarbonyl groups having from 1 to about12 carbon atoms, alkyl groups having from 1 to about 12 carbon atoms,amine groups having from 1 to about 12 carbon atoms or silyl groupshaving from 0 to about 12 carbon atoms.

Illustrative halogen atoms include, for example, fluorine, chlorine,bromine and iodine. Preferred halogen atoms include chlorine andfluorine.

Illustrative acyl groups include, for example, formyl, acetyl,propionyl, butyryl, isobutyryl, valeryl, 1-methylpropylcarbonyl,isovaleryl, pentylcarbonyl, 1-methylbutylcarbonyl,2-methylbutylcarbonyl, 3-methylbutylcarbonyl, 1-ethylpropylcarbonyl,2-ethylpropylcarbonyl, and the like. Preferred acyl groups includeformyl, acetyl and propionyl.

Illustrative alkoxy groups include, for example, methoxy, ethoxy,n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy,pentyloxy, 1-methylbutyloxy, 2-methylbutyloxy, 3-methylbutyloxy,1,2-dimethylpropyloxy, hexyloxy, 1-methylpentyloxy, 1-ethylpropyloxy,2-methylpentyloxy, 3-methylpentyloxy, 4-methylpentyloxy,1,2-dimethylbutyloxy, 1,3-dimethylbutyloxy, 2,3-dimethylbutyloxy,1,1-dimethylbutyloxy, 2,2-dimethylbutyloxy, 3,3-dimethylbutyloxy, andthe like. Preferred alkoxy groups include methoxy, ethoxy and propoxy.

Illustrative alkoxycarbonyl groups include, for example,methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl,cyclopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl,sec-butoxycarbonyl, tert-butoxycarbonyl, and the like. Preferredalkoxycarbonyl groups include methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, isopropoxycarbonyl and cyclopropoxycarbonyl.

Illustrative alkyl groups include, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl,neopentyl, tert-pentyl, 1-methylbutyl, 2-methylbutyl,1,2-dimethylpropyl, hexyl, isohexyl, 1-methylpentyl, 2-methylpentyl,3-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 1,3-dimethylbutyl,2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl,1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl,1-ethyl-2-methylpropyl, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, andthe like. Preferred alkyl groups include methyl, ethyl, n-propyl,isopropyl and cyclopropyl.

Illustrative amine groups include, for example, methylamine,dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine,isopropylamine, diisopropylamine, butylamine, dibutylamine,tert-butylamine, di(tert-butyl)amine, ethylmethylamine,butylmethylamine, cyclohexylamine, dicyclohexylamine, and the like.Preferred amine groups include dimethylamine, diethylamine anddiisopropylamine.

Illustrative silyl groups include, for example, silyl, trimethylsilyl,triethylsilyl, tris(trimethylsilyl)methyl, trisilylmethyl, methylsilyland the like. Preferred silyl groups include silyl, trimethylsilyl andtriethylsilyl.

Illustrative organometallic precursor compounds that can be made byprocess (1) of this invention include, for example,bis(N,N′-diisopropylacetamidinato)dinitrogenruthenium (II),bis(N,N′-diisopropylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diisopropylformamidinato)dinitrogenruthenium (II),bis(N,N′-diisopropylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-di-n-propylacetamidinato)dinitrogenruthenium (II),bis(N,N′-di-n-propylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-di-n-propylformamidinato)dinitrogenruthenium (II),bis(N,N′-di-n-propylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diethylacetamidinato)dinitrogenruthenium (II),bis(N,N′-diethylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diethylformamidinato)dinitrogenruthenium (II),bis(N,N′-diethylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-dimethylacetamidinato)dinitrogenruthenium (II),bis(N,N′-dimethylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-dimethylformamidinato)dinitrogenruthenium (II),bis(N,N′-dimethylformamidinato)di-trimethylphosphineruthenium (II), andthe like. In a preferred embodiment of process (1) of this invention, aruthenium (II) source starting material, e.g.,bis[dichloro(η⁶-benzene)ruthenium (II)], can be reacted with anamidinate starting material, e.g., lithium(N,N′-diisopropylacetamidinate), and nitrogen gas to give a ruthenium(II) amidinate product, e.g.,bis(N,N′-diisopropylacetamidinato)dinitrogenruthenium (II).

Illustrative organometallic precursor compounds that can be made byprocess (2) of this invention include, for example,tris(N,N′-diisopropylacetamidinato)ruthenium (III),tris(N,N′-diisopropylformamidinato)ruthenium (III),tris(N,N′-di-n-propylacetamidinato)ruthenium (III),tris(N,N′-di-n-propylformamidinato)ruthenium (III),tris(N,N′-diethylacetamidinato)ruthenium (III),tris(N,N′-diethylformamidinato)ruthenium (III),tris(N,N′-dimethylacetamidinato)ruthenium (III),tris(N,N′-dimethylformamidinato)ruthenium (III), and the like. In apreferred embodiment of process (2) of this invention, a ruthenium (II)source starting material, e.g., bis[dichloro(η⁶-benzene)ruthenium (II)],can be reacted with an amidinate starting material, e.g., lithium(N,N′-diisopropylacetamidinate), to give a ruthenium (III) amidinateproduct, e.g., tris(N,N′-diisopropylacetamidinato)ruthenium (III).

The processes are particularly well-suited for large scale productionsince they can be conducted using the same equipment, some of the samereagents and process parameters that can easily be adapted tomanufacture a wide range of products. The processes provide for thesynthesis of organometallic precursor compounds using processes whereall manipulations can be carried out in a single vessel, and which routeto the organometallic precursor compounds does not require the isolationof the metal source compound starting material or an intermediatecomplex.

The solvent employed in the process of this invention may be anysaturated and unsaturated hydrocarbons, aromatic hydrocarbons, aromaticheterocycles, alkyl halides, silylated hydrocarbons, ethers, polyethers,thioethers, esters, thioesters, lactones, amides, amines, polyamines,nitrites, silicone oils, other aprotic solvents, or mixtures of one ormore of the above; more preferably, diethylether, pentanes, ordimethoxyethanes; and most preferably hexanes or THF. Any suitablesolvent which does not unduly adversely interfere with the intendedreaction can be employed. Mixtures of one or more different solvents maybe employed if desired. The amount of solvent employed is not criticalto the subject invention and need only be that amount sufficient tosolubilize the reaction components in the reaction mixture. In general,the amount of solvent may range from about 5 percent by weight up toabout 99 percent by weight or more based on the total weight of thereaction mixture starting materials.

Reaction conditions for the reaction of the amidinate compound with themetal source compound and ligand source starting material, (i.e.,process (1) above) such as temperature, pressure and contact time, mayalso vary greatly and any suitable combination of such conditions may beemployed herein. The reaction temperature may be the reflux temperatureof any of the aforementioned solvents, and more preferably between about−80° C. to about 150° C., and most preferably between about 20° C. toabout 80° C. Normally the reaction is carried out under ambient pressureand the contact time may vary from a matter of seconds or minutes to afew hours or greater. The reactants can be added to the reaction mixtureor combined in any order. The stir time employed can range from about0.1 to about 400 hours, preferably from about 1 to 75 hours, and morepreferably from about 4 to 16 hours, for all steps.

Reaction conditions for the reaction of the amidinate compound with themetal source compound (i.e., process (2) above) such as temperature,pressure and contact time, may also vary greatly and any suitablecombination of such conditions may be employed herein. The reactiontemperature may be the reflux temperature of any of the aforementionedsolvents, and more preferably between about −80° C. to about 150° C.,and most preferably between about 20° C. to about 80° C. Normally thereaction is carried out under ambient pressure and the contact time mayvary from a matter of seconds or minutes to a few hours or greater. Thereactants can be added to the reaction mixture or combined in any order.The stir time employed can range from about 0.1 to about 400 hours,preferably from about 1 to 75 hours, and more preferably from about 4 to16 hours, for all steps.

Other alternative processes that may be used in preparing theorganometallic ruthenium compounds of this invention include thosedisclosed in U.S. Patent Application Publication No. US 2004/0127732 A1,published Jul. 1, 2004, the disclosure of which is incorporated hereinby reference. The organometallic precursor compounds of this inventionmay also be prepared by conventional processes such as described inVendemiati, Beatrice et al., Paramagnetic Bis(amidinate)Iron(II)Complexes and their Diamagnetic Dicarbonyl Derivatives, Euro. J. Inorg.Chem. 2001, 707-711; Lim, Booyong S. et al., Synthesis andCharacterization of Volatile, Thermally Stable, Reactive TransitionMetal Amidinates, Inorg. Chem., 2003, Preprint; and references therein.

For organometallic precursor compounds prepared by the processes of thisinvention, purification can occur through recrystallization, morepreferably through extraction of reaction residue (e.g., hexane) andchromatography, and most preferably through sublimation anddistillation.

Those skilled in the art will recognize that numerous changes may bemade to the processes described in detail herein, without departing inscope or spirit from the present invention as more particularly definedin the claims below.

Examples of techniques that can be employed to characterize theorganometallic precursor compounds formed by the synthetic processesdescribed above include, but are not limited to, analytical gaschromatography, nuclear magnetic resonance, thermogravimetric analysis,inductively coupled plasma mass spectrometry, differential scanningcalorimetry, vapor pressure and viscosity measurements.

The rate of vaporization, which correlates well with vapor pressure oforganometallic compound precursors described above within the confinesof the experiment, can be measured by thermogravimetric analysistechniques known in the art. Equilibrium vapor pressures also can bemeasured, for example by evacuating all gases from a sealed vessel,after which vapors of the compounds are introduced to the vessel and thepressure is measured as known in the art.

As indicated above, this invention also relates to organometallicruthenium precursor compounds represented by the formula

wherein R₁, R₂, R₃, R₄, R₅ and R₆ are the same or different and eachrepresents hydrogen, a halogen atom, an acyl group having from 1 toabout 12 carbon atoms, preferably from 1 to about 6 carbon atoms, analkoxy group having from 1 to about 12 carbon atoms, preferably from 1to about 6 carbon atoms, an alkoxycarbonyl group having from 1 to about12 carbon atoms, preferably from 1 to about 6 carbon atoms, an alkylgroup having from 1 to about 12 carbon atoms, preferably from 1 to about6 carbon atoms, an amine group having from 1 to about 12 carbon atoms,preferably from 1 to about 6 carbon atoms, or a silyl group having from0 to about 12 carbon atoms, preferably from 0 to about 6 carbon atoms,and L₁ and L₂ are the same or different and each represents N₂ or asubstituted or unsubstituted heteroatom-containing group. Illustrativesuch groups are set forth above.

Illustrative organometallic ruthenium precursor compounds represented bythe above formula includebis(N,N′-diisopropylacetamidinato)dinitrogenruthenium (II),bis(N,N′diisopropylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diisopropylformamidinato)dinitrogenruthenium (II),bis(N,N′-diisopropylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-di-n-propylacetamidinato)dinitrogenruthenium (II),bis(N,N′-di-n-propylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-di-n-propylformamidinato)dinitrogenruthenium (II),bis(N,N′-di-n-propylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diethylacetamidinato)dinitrogenruthenium (II),bis(N,N′-diethylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diethylformamidinato)dinitrogenruthenium (II),bis(N,N′-diethylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-dimethylacetamidinato)dinitrogenruthenium (II),bis(N,N′-dimethylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-dimethylformamidinato)dinitrogenruthenium (II), andbis(N,N′-dimethylformamidinato)di-trimethylphosphineruthenium (II).

The organometallic compound precursors described herein are preferablyhydrogen reducible, deposit in a self-limiting manner, liquid at roomtemperature, i.e., 20° C., and are well suited for preparing in-situpowders and coatings. For instance, a liquid organometallic compoundprecursor can be applied to a substrate and then heated to a temperaturesufficient to decompose the precursor, thereby forming a metal or metaloxide coating on the substrate. Applying a liquid precursor to thesubstrate can be by painting, spraying, dipping or by other techniquesknown in the art. Heating can be conducted in an oven, with a heat gun,by electrically heating the substrate, or by other means, as known inthe art. A layered coating can be obtained by applying an organometalliccompound precursor, and heating and decomposing it, thereby forming afirst layer, followed by at least one other coating with the same ordifferent precursors, and heating.

Liquid organometallic compound precursors such as described above alsocan be atomized and sprayed onto a substrate. Atomization and sprayingmeans, such as nozzles, nebulizers and others, that can be employed areknown in the art.

In preferred embodiments of the invention, an organometallic compound,such as described above, is employed in gas phase deposition techniquesfor forming powders, films or coatings. The compound can be employed asa single source precursor or can be used together with one or more otherprecursors, for instance, with vapor generated by heating at least oneother organometallic compound or metal complex. More than oneorganometallic compound precursor, such as described above, also can beemployed in a given process.

As indicated above, this invention relates to organometallic precursormixtures comprising (i) a first organometallic precursor compoundrepresented by the formula (L)₂M(L′)₂ or M(L)₃ above and (ii) one ormore different organometallic precursor compounds (e.g., ahafnium-containing, tantalum-containing or molybdenum-containingorganometallic precursor compound).

Deposition can be conducted in the presence of other gas phasecomponents. In an embodiment of the invention, film deposition isconducted in the presence of at least one non-reactive carrier gas.Examples of non-reactive gases include inert gases, e.g., nitrogen,argon, helium, as well as other gases that do not react with theorganometallic compound precursor under process conditions. In otherembodiments, film deposition is conducted in the presence of at leastone reactive gas. Some of the reactive gases that may be employedinclude but are not limited to hydrazine, oxygen, hydrogen, air,oxygen-enriched air, ozone (O₃), nitrous oxide (N₂O), water vapor,organic vapors, ammonia and others. As known in the art, the presence ofan oxidizing gas, such as, for example, air, oxygen, oxygen-enrichedair, O₃, N₂O or a vapor of an oxidizing organic compound, favors theformation of a metal oxide film.

In an embodiment, hydrogen or another reducing gas may be used in a BEOLatomic layer deposition process at temperatures below 300° C. so thatthe deposition can be carried out in a manner compatible with the restof the BEOL integration strategy. Hydrogen reducible ruthenium complexesmay also be used for the integration of ruthenium in MIM stacked cellDRAM capacitors.

In addition to being hydrogen reducible, the ruthenium complexes of thisinvention deposit in a self-limiting manner. For example, in the absenceof a reactant gas, the substrate becomes saturated with a monolayer, orfraction of a monolayer, of the dissociatively chemisorbed rutheniumprecursor. In a self-limiting deposition, only one layer oforganometallic precursor is deposited at a time. Amidinate-basedruthenium precursors deposited in a self-limiting manner by atomic layerdeposition may enable conformal film growth over high aspect ratiotrench architectures in a reducing environment.

As indicated above, this invention also relates in part to a method forproducing a film, coating or powder. The method includes the step ofdecomposing at least one organometallic compound precursor, therebyproducing the film, coating or powder, as further described below.

Deposition methods described herein can be conducted to form a film,powder or coating that includes a single metal or a film, powder orcoating that includes a single metal oxide. Mixed films, powders orcoatings also can be deposited, for instance mixed metal oxide films. Amixed metal oxide film can be formed, for example, by employing severalorganometallic precursors, at least one of which being selected from theorganometallic compounds described above.

Gas phase film deposition can be conducted to form film layers of adesired thickness, for example, in the range of from about 1 nm to over1 mm. The precursors described herein are particularly useful forproducing thin films, e.g., films having a thickness in the range offrom about 10 nm to about 100 nm. Films of this invention, for instance,can be considered for fabricating metal electrodes, in particular asn-channel metal electrodes in logic, as capacitor electrodes for DRAMapplications, and as dielectric materials.

The method also is suited for preparing layered films, wherein at leasttwo of the layers differ in phase or composition. Examples of layeredfilm include metal-insulator-semiconductor, and metal-insulator-metal.

In an embodiment, the invention is directed to a method that includesthe step of decomposing vapor of an organometallic compound precursordescribed above, thermally, chemically, photochemically or by plasmaactivation, thereby forming a film on a substrate. For instance, vaporgenerated by the compound is contacted with a substrate having atemperature sufficient to cause the organometallic compound to decomposeand form a film on the substrate.

The organometallic compound precursors can be employed in chemical vapordeposition or, more specifically, in metalorganic chemical vapordeposition processes known in the art. For instance, the organometalliccompound precursors described above can be used in atmospheric, as wellas in low pressure, chemical vapor deposition processes. The compoundscan be employed in hot wall chemical vapor deposition, a method in whichthe entire reaction chamber is heated, as well as in cold or warm walltype chemical vapor deposition, a technique in which only the substrateis being heated.

The organometallic compound precursors described above also can be usedin plasma or photo-assisted chemical vapor deposition processes, inwhich the energy from a plasma or electromagnetic energy, respectively,is used to activate the chemical vapor deposition precursor. Thecompounds also can be employed in ion-beam, electron-beam assistedchemical vapor deposition processes in which, respectively, an ion beamor electron beam is directed to the substrate to supply energy fordecomposing a chemical vapor deposition precursor. Laser-assistedchemical vapor deposition processes, in which laser light is directed tothe substrate to affect photolytic reactions of the chemical vapordeposition precursor, also can be used.

The method of the invention can be conducted in various chemical vapordeposition reactors, such as, for instance, hot or cold-wall reactors,plasma-assisted, beam-assisted or laser-assisted reactors, as known inthe art.

Examples of substrates that can be coated employing the method of theinvention include solid substrates such as metal substrates, e.g., Al,Ni, Ti, Co, Pt, Ta; metal silicides, e.g., TiSi₂, CoSi₂, NiSi₂;semiconductor materials, e.g., Si, SiGe, GaAs, InP, diamond, GaN, SiC;insulators, e.g., SiO₂, Si₃N₄, HfO₂, HfSiO₂, HfSiON, Ta₂O₅, Al₂O₃,barium strontium titanate (BST); barrier materials, e.g., TiN, TaN, WN,WSiN, TaSiN; or on substrates that include combinations of materials. Inaddition, films or coatings can be formed on glass, ceramics, plastics,thermoset polymeric materials, and on other coatings or film layers. Inpreferred embodiments, film deposition is on a substrate used in themanufacture or processing of electronic components. In otherembodiments, a substrate is employed to support a low resistivityconductor deposit that is stable in the presence of an oxidizer at hightemperature or an optically transmitting film.

The method of this invention can be conducted to deposit a film on asubstrate that has a smooth, flat surface. In an embodiment, the methodis conducted to deposit a film on a substrate used in wafermanufacturing or processing. For instance, the method can be conductedto deposit a film on patterned substrates that include features such astrenches, holes or vias. Furthermore, the method of the invention alsocan be integrated with other steps in wafer manufacturing or processing,e.g., masking, etching and others.

Chemical vapor deposition films can be deposited to a desired thickness.For example, films formed can be less than 1 micron thick, preferablyless than 500 nanometers and more preferably less than 200 nanometersthick. Films that are less than 50 nanometers thick, for instance, filmsthat have a thickness between about 1 and about 20 nanometers, also maybe produced. Atomic layer deposition films can also be deposited to adesired thickness. For example, films formed can be less than 500nanometers thick, preferably less than 50 nanometers and more preferablybetween 2 to 5 nanometers thick.

Organometallic compound precursors described above also can be employedin the method of the invention to form films by atomic layer deposition(ALD) or atomic layer nucleation (ALN) techniques, during which asubstrate is exposed to alternate pulses of precursor, reactant gas andinert gas streams. Sequential layer deposition techniques are described,for example, in U.S. Pat. No. 6,287,965 and in U.S. Pat. No. 6,342,277.The disclosures of both patents are incorporated herein by reference intheir entirety.

For example, in one ALD cycle, a substrate is exposed, in step-wisemanner, to: a) an inert gas; b) inert gas carrying precursor vapor; c)inert gas; and d) a reactant, alone or together with inert gas. Ingeneral, each step can be as short as the equipment will permit (e.g.milliseconds) and as long as the process requires (e.g. several secondsor minutes). The duration of one cycle can be as short as millisecondsand as long as minutes. The cycle is repeated over a period that canrange from a few minutes to hours. Film produced can be a few nanometersthin or thicker, e.g., 1 millimeter (mm).

The method of the invention also can be conducted using supercriticalfluids. Examples of film deposition methods that use supercritical fluidthat are currently known in the art include chemical fluid deposition;supercritical fluid transport-chemical deposition; supercritical fluidchemical deposition; and supercritical immersion deposition.

Chemical fluid deposition processes, for example, are well suited forproducing high purity films and for covering complex surfaces andfilling of high-aspect-ratio features. Chemical fluid deposition isdescribed, for instance, in U.S. Pat. No. 5,789,027. The use ofsupercritical fluids to form films also is described in U.S. Pat. No.6,541,278 B2. The disclosures of these two patents are incorporatedherein by reference in their entirety.

In an embodiment of the invention, a heated patterned substrate isexposed to one or more organometallic compound precursors, in thepresence of a solvent, such as a near critical or supercritical fluid,e.g., near critical or supercritical CO₂. In the case of CO₂, thesolvent fluid is provided at a pressure above about 1000 psig and atemperature of at least about 30° C.

The precursor is decomposed to form a metal film on the substrate. Thereaction also generates organic material from the precursor. The organicmaterial is solubilized by the solvent fluid and easily removed awayfrom the substrate. Metal oxide films also can be formed, for example byusing an oxidizing gas.

In an example, the deposition process is conducted in a reaction chamberthat houses one or more substrates. The substrates are heated to thedesired temperature by heating the entire chamber, for instance, bymeans of a furnace. Vapor of the organometallic compound can beproduced, for example, by applying a vacuum to the chamber. For lowboiling compounds, the chamber can be hot enough to cause vaporizationof the compound. As the vapor contacts the heated substrate surface, itdecomposes and forms a metal or metal oxide film. As described above, anorganometallic compound precursor can be used alone or in combinationwith one or more components, such as, for example, other organometallicprecursors, inert carrier gases or reactive gases.

In a system that can be used in producing films by the method of theinvention, raw materials can be directed to a gas-blending manifold toproduce process gas that is supplied to a deposition reactor, where filmgrowth is conducted. Raw materials include, but are not limited to,carrier gases, reactive gases, purge gases, precursor, etch/clean gases,and others. Precise control of the process gas composition isaccomplished using mass-flow controllers, valves, pressure transducers,and other means, as known in the art. An exhaust manifold can convey gasexiting the deposition reactor, as well as a bypass stream, to a vacuumpump. An abatement system, downstream of the vacuum pump, can be used toremove any hazardous materials from the exhaust gas. The depositionsystem can be equipped with in-situ analysis system, including aresidual gas analyzer, which permits measurement of the process gascomposition. A control and data acquisition system can monitor thevarious process parameters (e.g., temperature, pressure, flow rate,etc.).

The organometallic compound precursors described above can be employedto produce films that include a single metal or a film that includes asingle metal oxide. Mixed films also can be deposited, for instancemixed metal oxide films. Such films are produced, for example, byemploying several organometallic precursors. Metal films also can beformed, for example, by using no carrier gas, vapor or other sources ofoxygen.

Films formed by the methods described herein can be characterized bytechniques known in the art, for instance, by X-ray diffraction, Augerspectroscopy, X-ray photoelectron emission spectroscopy, atomic forcemicroscopy, scanning electron microscopy, and other techniques known inthe art. Resistivity and thermal stability of the films also can bemeasured, by methods known in the art.

Various modifications and variations of this invention will be obviousto a worker skilled in the art and it is to be understood that suchmodifications and variations are to be included within the purview ofthis application and the spirit and scope of the claims.

EXAMPLE 1 Synthesis of lithium (N,N′-diisopropylacetamidinate)

A dry 500 milliliter 3-neck round-bottom flask was equipped with a 100milliliter dropping funnel, a Teflon stir bar, and a thermocouple. Thesystem was connected to an inert atmosphere (N₂) nitrogen manifold andthe remaining outlets were sealed with rubber septa. To this flask wasadded 155 milliliters of tetrahydrofuran (THF) and 13.99 grams ofdiisopropylcarbodiimide. The solution was cooled to −50° C. by use of adry ice/acetone bath. 72 milliliters of 1.6M MeLi in diethyl ether wasadded to the dropping funnel. The MeLi solution was added dropwise tothe diisopropylcarbodiimide solution at a rate sufficiently slow to keepthe temperature of the solution below −30° C. Following the addition thesolution was allowed to warm to room temperature overnight. The paleyellow solution can be used either as a solution of lithiumN,N′-diisopropylacetamidinate) or the solvent can be removed to isolatethe salt.

Synthesis of Bis[dichloro(η⁶-benzene)ruthenium (II)]

A procedure adapted from the one outlined in Inorganic Syntheses, Vol21, page 75 was followed. A dry 500 milliliter 3-neck round-bottom flaskwas charged with 6 grams of RuCl₃.H₂O and 300 milliliters of ethanol.The solution was purged with nitrogen. To this solution, 30 millilitersof 1,3-cyclohexadiene was added. The solution was refluxed for 4 hours.Dark orange solids became evident during this time and the color of thesolution changed from an opaque, deep orange color to a clear paleyellow solution. The product was filtered through a coarse frit andisolated. 5.8 grams of bis[dichloro(η⁶-benzene)ruthenium (II)] wasisolated in this manner. The product was dried in a vacuum oven toremove residual ethanol.

Synthesis of Tris(N,N′-diisopropylacetamidinato)ruthenium (III) andBis(N,N′-diisopropylacetamidinato)dinitrogenruthenium (II)

In a 250 milliliter round-bottomed flask, 5.0 grams ofbis[dichloro(η⁶-benzene)ruthenium (II)] and a Teflon stir bar wereadded. The flask was fitted with a thermocouple and reflux condenser andconnected to an inert atmosphere/nitrogen manifold, and the remainingoutlets were sealed with rubber septa. The flask was evacuated andrefilled with nitrogen three times. To this system, 4 equivalents oflithium (N,N′-diisopropylacetamidinate) salt were added as a THF/diethylether solution. The solution was refluxed for 16 hours. Following therefluxing of the solution, the solution was filtered, and the solventwas removed under reduced pressure. 3.1 grams of crude material wasrecovered in this manner. The crude material was sublimed in 2fractions. The first fraction was initially colorless and developed apale blue color as the temperature was ramped from 30° C. to 70° C. Thesecond fraction was collected as the temperature of the oil bath beneaththe sublimator ramped between 80° C. and 130° C. 120 milligrams of bluecrystals were collected.

GC/MS analysis showed two peaks in a cyclohexane solution run of theblue crystals. The first peak integrating for approximately 5% of thetotal intensity of the two peaks had a mass of 440 Da/e⁻ and showed anisotope pattern consistent withbis(N,N′-diisopropylacetamidinato)dinitrogenruthenium (II)(iPr-Me-AMD)₂(N₂)₂Ru and a fragmentation pattern consistent with theloss of two dinitrogen ligands. The second peak had a mass of 525 Da/e⁻and showed an isotope-pattern and fragmentation pattern consistent withthe assignment tris(N,N′-diisopropylacetamidinato)ruthenium (III)(iPr-Me-AMD)₃Ru. The reaction scheme can be depicted as follows:

2 Li(iPr-Me-AMD)+[(C₆H₆)RuCl₂]₂→Ru(iPr-Me-AMD)₃+Ru(iPr-Me-AMD)₂(N₂)₂

1. A process for the production of an organometallic compoundrepresented by the formula (L)₂M(L′)₂ which process consists essentiallyof (i) reacting a substituted or unsubstituted metal source compoundrepresented by the formula MX₂R with a substituted or unsubstitutedamidinate or amidinate-like compound represented by the formula A₁L anda ligand source represented by the formula L′, said ligand source L′present in an amount sufficient to coordinate directly to M, in thepresence of a solvent and under reaction conditions sufficient toproduce a reaction mixture comprising said organometallic compound, and(ii) separating said organometallic compound from said reaction mixture;wherein M is a Group VIII metal, X is a halogen group, R is asubstituted or unsubstituted hydrocarbon group, A₁ is an alkali metal, Lis the same or different and represents a substituted or unsubstitutedamidinato group or a substituted or unsubstituted amidinato-like group,and L′ is the same or different and represents N₂ or a substituted orunsubstituted heteroatom-containing group.
 2. The process of claim 1wherein, in the metal source compound represented by the formula MX₂R, Mis Ru, Os or Fe, X is fluoro, chloro, bromo or iodo, and R is η⁶-benzeneor η⁶-toluene.
 3. The process of claim 1 wherein the metal sourcecompound is selected from bis[dichloro(η⁶-benzene)ruthenium (II)] andbis[dichloro(η⁶-toluene)ruthenium (II)].
 4. The process of claim 1wherein, in the amidinate or amidinate-like compound represented by theformula A₁L, A₁ is lithium, sodium or bromium and L is an amidinatogroup or a negatively charged, chelating, four electron donor group. 5.The process of claim 1 wherein the amidinate or amidinate-like compoundis selected from lithium (N,N′-diisopropylacetamidinate), lithium(N,N′-diisopropylformamidinate), lithium(N,N′-di-n-propylacetamidinate), lithium(N,N′-di-n-propylformamidinate), lithium (N,N′-diethylacetamidinate),lithium (N,N′-diethylformamidinate), lithium(N,N′-dimethylacetamidinate), and lithium (N,N′-dimethylformamidinate).6. The process of claim 1 wherein the ligand source represented by theformula L′ is selected from N₂, NCR₇, PR₇R₈R₉ or NR₇R₈R₉, wherein R₇, R₈and R₉ are the same or different and each represents hydrogen, a halogenatom, an acyl group having from 1 to about 12 carbon atoms, an alkoxygroup having from 1 to about 12 carbon atoms, an alkoxycarbonyl grouphaving from 1 to about 12 carbon atoms, an alkyl group having from 1 toabout 12 carbon atoms, an amine group having from 1 to about 12 carbonatoms or a silyl group having from 0 to about 12 carbon atoms.
 7. Theprocess of claim 1 wherein the organometallic compound comprisesbis(N,N′-diisopropylacetamidinato)dinitrogenruthenium (II),bis(N,N′-diisopropylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diisopropylformamidinato)dinitrogenruthenium (II),bis(N,N′-diisopropylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-di-n-propylacetamidinato)dinitrogenruthenium (II),bis(N,N′-di-n-propylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-di-n-propylformamidinato)dinitrogenruthenium (II),bis(N,N′-di-n-propylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diethylacetamidinato)dinitrogenruthenium (II),bis(N,N′-diethylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-diethylformamidinato)dinitrogenruthenium (II),bis(N,N′-diethylformamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-dimethylacetamidinato)dinitrogenruthenium (II),bis(N,N′-dimethylacetamidinato)di-trimethylphosphineruthenium (II),bis(N,N′-dimethylformamidinato)dinitrogenruthenium (II), andbis(N,N′-dimethylformamidinato)di-trimethylphosphineruthenium (II). 8.The process of claim 1 wherein the solvent is selected from saturatedand unsaturated hydrocarbons, aromatic hydrocarbons, aromaticheterocycles, alkyl halides, silylated hydrocarbons, ethers, polyethers,thioethers, esters, thioesters, lactones, amides, amines, polyamines,nitriles, silicone oils, other aprotic solvents, or mixtures of one ormore of the above.
 9. The process of claim 1 wherein the organometalliccompound is represented by the formula

wherein R₁, R₂, R₃, R₄, R₅ and R₆ are the same or different and eachrepresents hydrogen, a halogen atom, an acyl group having from 1 toabout 12 carbon atoms, an alkoxy group having from 1 to about 12 carbonatoms, an alkoxycarbonyl group having from 1 to about 12 carbon atoms,an alkyl group having from 1 to about 12 carbon atoms, an amine grouphaving from 1 to about 12 carbon atoms or a silyl group having from 0 toabout 12 carbon atoms, and L₁ and L₂ are the same or different and eachrepresents N₂ or a substituted or unsubstituted heteroatom-containinggroup.